A comprehensive review of green hydrogen pathways and applications in emerging energy systems

Abstract

The transition to a sustainable energy future has increased the attention to green hydrogen as a The transition to a sustainable energy future has intensified interest in green hydrogen as a transformative low-carbon energy carrier. This study provides a comprehensive overview of green hydrogen production pathways, including biomass thermochemical processes and water-splitting routes such as electrolysis, thermolysis, and photolysis, with emphasis on their efficiencies, scalability, and technical challenges. In addition, storage and transportation options—such as physical and material-based methods, liquefaction, pipelines, and hydrogen carrier technologies—are critically examined alongside key techno-economic and safety considerations. The study further explores the application of green hydrogen in power generation, industrial decarbonization, transportation, and distributed energy systems, highlighting its role in sector coupling and enhancing grid flexibility. The findings indicate that while green hydrogen holds significant potential for deep decarbonization, its large-scale deployment requires coordinated policy support, cost reduction strategies, and substantial infrastructure development. This work concludes with strategic recommendations for policymakers, researchers, and industry stakeholders regarding investment priorities and the future scale-up of green hydrogen technologies.